1. Field of Invention
The invention relates to electric plugs and more particularly to an improved waterproof electric plug having a transformer.
2. Description of Related Art
Alternating current (AC) power is required to transform into direct current (DC) power prior to supplying to small electric/electronic products such as mobile phones, lamps, Christmas lamp strings, etc. For example, plugs of Christmas lamp strings are required to be waterproof because in often times they are used outsides. Rain, water, and moisture may enter plugs that are not waterproof when the plugs are used outsides. This can cause short circuit to the plugs.
However, many types of waterproof electric plugs having a transformer for Christmas lamp strings have complicated components and poor quality. U.S. Pat. No. 7,140,920 discloses an electric plug comprising two forward prongs, two rear slots, two conductive wires having one end disposed in the housing, and an internal resistor electrically interconnecting the prongs and the wires. However, such configured plugs are not waterproof. Moreover, the components are relatively complicated.
Another conventional waterproof electric plug comprises a transformer in a housing, and a rear cover sealed the housing. Moreover, plastic are molded onto the housing and the seal to form a waterproof construction. However, its production cost is prohibitively high and its assembly is complicated and time consuming. Thus, the need for improvement still exists.